Income inequality differs tremendously across the countries of the world. It remains central even in the age of globalisation because most relevant political decisions are still made on the national level. In recent years, within-country inequalities have risen, while inequalities among nations have decreased. This paper argues that intra-national inequality of income is decisively shaped by the interaction between class formation/stratification and ethnic differentiation. This inequality is greatly exacerbated if an ethnic class stratification has evolved, i.e. if social class differences coincide with ethnic differences. Following Weber's idea of sociology as a science of reality it is argued that the diversity and complexity of types of ethnic stratification can best be grasped by defining ideal-typical strategies and stratification patterns that have developed in different regions and cultures of the world. Three basic types are distinguished: strategies for the preservation or restoration of ethnic homogeneity, strategies to control the formation of ethnic heterogeneity, and strategies to establish the rule of ethno classes. Country differences in income inequality can be plausibly explained using this typology.